playlist_print: added wrappers for printing the queue

Hide the details of the playlist behind wrapper functions.

src/command.c

@@ -421,12 +421,7 @@ static enum command_return
 handle_currentsong(struct client *client,
 		   G_GNUC_UNUSED int argc, G_GNUC_UNUSED char *argv[])
 {
-	int song = getPlaylistCurrentSong(&g_playlist);
+	playlist_print_current(client, &g_playlist);
-	const struct queue *queue = playlist_get_queue(&g_playlist);
-
-	if (song >= 0)
-		queue_print_info(client, queue, song, song + 1);
-
 	return PLAYLIST_RESULT_SUCCESS;
 }
 
@@ -642,9 +637,7 @@ static enum command_return
 handle_playlist(struct client *client,
 	        G_GNUC_UNUSED int argc, G_GNUC_UNUSED char *argv[])
 {
-	const struct queue *queue = playlist_get_queue(&g_playlist);
+	playlist_print_uris(client, &g_playlist);
-
-	queue_print_uris(client, queue, 0, queue_length(queue));
 	return COMMAND_RETURN_OK;
 }
 
@@ -766,12 +759,11 @@ static enum command_return
 handle_plchanges(struct client *client, G_GNUC_UNUSED int argc, char *argv[])
 {
 	uint32_t version;
-	const struct queue *queue = playlist_get_queue(&g_playlist);
 
 	if (!check_uint32(client, &version, argv[1], need_positive))
 		return COMMAND_RETURN_ERROR;
 
-	queue_print_changes_info(client, queue, version);
+	playlist_print_changes_info(client, &g_playlist, version);
 	return COMMAND_RETURN_OK;
 }
 
@@ -779,12 +771,11 @@ static enum command_return
 handle_plchangesposid(struct client *client, G_GNUC_UNUSED int argc, char *argv[])
 {
 	uint32_t version;
-	const struct queue *queue = playlist_get_queue(&g_playlist);
 
 	if (!check_uint32(client, &version, argv[1], need_positive))
 		return COMMAND_RETURN_ERROR;
 
-	queue_print_changes_position(client, queue, version);
+	playlist_print_changes_position(client, &g_playlist, version);
 	return COMMAND_RETURN_OK;
 }
 
@@ -792,46 +783,37 @@ static enum command_return
 handle_playlistinfo(struct client *client, int argc, char *argv[])
 {
 	unsigned start = 0, end = UINT_MAX;
-	const struct queue *queue = playlist_get_queue(&g_playlist);
+	bool ret;
 
 	if (argc == 2 && !check_range(client, &start, &end,
 				      argv[1], need_range))
 		return COMMAND_RETURN_ERROR;
 
-	if (end > queue_length(queue))
+	ret = playlist_print_info(client, &g_playlist, start, end);
-		end = queue_length(queue);
+	if (!ret)
-
-	if (start > end)
 		return print_playlist_result(client,
 					     PLAYLIST_RESULT_BAD_RANGE);
 
-	queue_print_info(client, queue, start, end);
 	return COMMAND_RETURN_OK;
 }
 
 static enum command_return
 handle_playlistid(struct client *client, int argc, char *argv[])
 {
-	int id = -1, start;
+	int id = -1;
-	unsigned end;
-	const struct queue *queue = playlist_get_queue(&g_playlist);
 
 	if (argc == 2 && !check_int(client, &id, argv[1], need_positive))
 		return COMMAND_RETURN_ERROR;
 
 	if (id >= 0) {
-		start = queue_id_to_position(queue, id);
+		bool ret = playlist_print_id(client, &g_playlist, id);
-		if (start < 0)
+		if (!ret)
 			return print_playlist_result(client,
 						     PLAYLIST_RESULT_NO_SUCH_SONG);
-
-		end = start + 1;
 	} else {
-		start = 0;
+		playlist_print_info(client, &g_playlist, 0, UINT_MAX);
-		end = queue_length(queue);
 	}
 
-	queue_print_info(client, queue, start, end);
 	return COMMAND_RETURN_OK;
 }
 
@@ -924,7 +906,7 @@ handle_playlistfind(struct client *client, int argc, char *argv[])
 		return COMMAND_RETURN_ERROR;
 	}
 
-	queue_find(client, playlist_get_queue(&g_playlist), list);
+	playlist_print_find(client, &g_playlist, list);
 
 	locate_item_list_free(list);
 
@@ -945,7 +927,7 @@ handle_playlistsearch(struct client *client, int argc, char *argv[])
 		return COMMAND_RETURN_ERROR;
 	}
 
-	queue_search(client, playlist_get_queue(&g_playlist), list);
+	playlist_print_search(client, &g_playlist, list);
 
 	locate_item_list_free(list);
 

src/playlist_print.c

@@ -17,12 +17,97 @@
  */
 
 #include "playlist_print.h"
+#include "queue_print.h"
 #include "stored_playlist.h"
 #include "song_print.h"
 #include "song.h"
 #include "database.h"
 #include "client.h"
 
+void
+playlist_print_uris(struct client *client, const struct playlist *playlist)
+{
+	const struct queue *queue = &playlist->queue;
+
+	queue_print_uris(client, queue, 0, queue_length(queue));
+}
+
+bool
+playlist_print_info(struct client *client, const struct playlist *playlist,
+		    unsigned start, unsigned end)
+{
+	const struct queue *queue = &playlist->queue;
+
+	if (end > queue_length(queue))
+		/* correct the "end" offset */
+		end = queue_length(queue);
+
+	if (start > end)
+		/* an invalid "start" offset is fatal */
+		return false;
+
+	queue_print_info(client, queue, start, end);
+	return true;
+}
+
+bool
+playlist_print_id(struct client *client, const struct playlist *playlist,
+		  unsigned id)
+{
+	const struct queue *queue = &playlist->queue;
+	int position;
+
+	position = queue_id_to_position(queue, id);
+	if (position < 0)
+		/* no such song */
+		return false;
+
+	return playlist_print_info(client, playlist, position, position + 1);
+}
+
+bool
+playlist_print_current(struct client *client, const struct playlist *playlist)
+{
+	int current_position = getPlaylistCurrentSong(playlist);
+
+	if (current_position < 0)
+		return false;
+
+	queue_print_info(client, &playlist->queue,
+			 current_position, current_position + 1);
+	return true;
+}
+
+void
+playlist_print_find(struct client *client, const struct playlist *playlist,
+		    const struct locate_item_list *list)
+{
+	queue_find(client, &playlist->queue, list);
+}
+
+void
+playlist_print_search(struct client *client, const struct playlist *playlist,
+		      const struct locate_item_list *list)
+{
+	queue_search(client, &playlist->queue, list);
+}
+
+void
+playlist_print_changes_info(struct client *client,
+			    const struct playlist *playlist,
+			    uint32_t version)
+{
+	queue_print_changes_info(client, &playlist->queue, version);
+}
+
+void
+playlist_print_changes_position(struct client *client,
+				const struct playlist *playlist,
+				uint32_t version)
+{
+	queue_print_changes_position(client, &playlist->queue, version);
+}
+
 bool
 spl_print(struct client *client, const char *name_utf8, bool detail)
 {

src/playlist_print.h

@@ -20,8 +20,74 @@
 #define PLAYLIST_PRINT_H
 
 #include <stdbool.h>
+#include <stdint.h>
 
 struct client;
+struct playlist;
+struct locate_item_list;
+
+/**
+ * Sends the whole playlist to the client, song URIs only.
+ */
+void
+playlist_print_uris(struct client *client, const struct playlist *playlist);
+
+/**
+ * Sends a range of the playlist to the client, including all known
+ * information about the songs.  The "end" offset is decreased
+ * automatically if it is too large; passing UINT_MAX is allowed.
+ * This function however fails when the start offset is invalid.
+ */
+bool
+playlist_print_info(struct client *client, const struct playlist *playlist,
+		    unsigned start, unsigned end);
+
+/**
+ * Sends the song with the specified id to the client.
+ *
+ * @return true on suite, false if there is no such song
+ */
+bool
+playlist_print_id(struct client *client, const struct playlist *playlist,
+		  unsigned id);
+
+/**
+ * Sends the current song to the client.
+ *
+ * @return true on success, false if there is no current song
+ */
+bool
+playlist_print_current(struct client *client, const struct playlist *playlist);
+
+/**
+ * Find songs in the playlist.
+ */
+void
+playlist_print_find(struct client *client, const struct playlist *playlist,
+		    const struct locate_item_list *list);
+
+/**
+ * Search for songs in the playlist.
+ */
+void
+playlist_print_search(struct client *client, const struct playlist *playlist,
+		      const struct locate_item_list *list);
+
+/**
+ * Print detailed changes since the specified playlist version.
+ */
+void
+playlist_print_changes_info(struct client *client,
+			    const struct playlist *playlist,
+			    uint32_t version);
+
+/**
+ * Print changes since the specified playlist version, position only.
+ */
+void
+playlist_print_changes_position(struct client *client,
+				const struct playlist *playlist,
+				uint32_t version);
 
 /**
  * Send the stored playlist to the client.